Natural gas injection into a blast furnace typically occurs through a pipe or tube fitted through the side wall of the blowpipe or tuyere. Under ideal conditions, natural gas reacts with oxygen contained in the hot blast through the blowpipe or tuyere according to reaction (1) to produce combustion products and release energy.CH4+2O2→CO2+2H2O  (1)
Once these gases reach the hot coke bed at the edge of the raceway they are converted into the CO and H2 that reduce the iron ore.
However, several factors make blast furnace injection conditions less than ideal. The gas floods into the tuyere and raceway with limited opportunity for mixing with the hot blast. The poor mixing is compounded by the high gas velocities through this area—in excess of 200 m/s—so residence times are only a few milliseconds. As a result, only partial combustion of the natural gas takes place. Once the gases leave the raceway they enter the coke bed where any remaining oxygen reacts immediately with the hot coke. Once this occurs further combustion of the natural gas is not possible.
As a result of these factors, significant fractions of the natural gas do not react with oxygen but instead decompose thermally according to reaction (2):CH4→C+2H2  (2)
Although the hydrogen thus produced is used beneficially in the blast furnace for smelting iron ore, the carbon soot is relatively unreactive. As a result much of this carbon passes through the blast furnace and is lost to the dust and sludge collected in the gas cleaning system. In addition the added load of fine particles (i.e., carbon soot) is detrimental to furnace operation. Improved utilization of this carbon is a significant opportunity for reduced blast furnace operating cost and improved operational performance.
Previous approaches in the prior art to improving the efficiency of natural gas use include the following.                Curved Injection Pipe—An injection pipe is used which is curved such that its discharge is opposite to the flow of the hot blast through the blowpipe and tuyere. The idea is that introducing the natural gas in a direction of flow contrary to the direction of the hot blast through the blowpipe would increase mixing and residence time.        The curved lance approach creates operational difficulties in that the lance cannot be changed without removing the entire tuyere.        Mixing Station—A mixing station is used to introduce limited quantities of oxygen into the natural gas to reduce the time required for oxygen and natural gas to mix in the tuyere and raceway.        The mixing station approach requires installation of capital equipment to achieve the mixing, and important control equipment to ensure that explosive oxygen/NG mixtures are not created. A source of oxygen is required to support this approach. Also, the admixed oxygen is injected cold and adds an undesirable thermal load to the furnace.        
There is therefore a need for an apparatus and a method for injection of natural gas and/or other fluid hydrocarbons into a blast furnace which overcomes or mitigates one or more of the disadvantages of the prior art.